Risk factors for critical COVID-19 illness during Delta- and Omicron-predominant period in Korea; using K-COV-N cohort in the National health insurance service.

BACKGROUND: This study evaluated the clinical characteristics of patients with COVID-19 in Korea, and examined the relationship between severe COVID-19 cases and underlying health conditions during the Delta (September 20, 2021 to December 4, 2021) and the Omicron (February 20, 2022 to March 31, 2022) predominant period. METHODS: This study assessed the association between critical COVID-19 illness and various risk factors, including a variety of underlying health conditions, using multiple logistic regression models based on the K-COV-N cohort, a nationwide data of confirmed COVID-19 cases linked with COVID-19 vaccination status and the National Health Insurance claim information. RESULTS: We analyzed 137,532 and 8,294,249 cases of COVID-19 infection during the Delta and the Omicron variant dominant periods, respectively. During the Delta as well as the Omicron period, old age (≥80 years) showed the largest effect size among risk factors for critical COVID-19 illness (aOR = 18.08; 95% confidence interval [CI] = 14.71-22.23 for the Delta; aOR = 24.07; 95% CI = 19.03-30.44 for the Omicron period). We found that patients with solid organ transplant (SOT) recipients, unvaccinated, and interstitial lung disease had more than a two-fold increased risk of critical COVID-19 outcomes between the Delta and Omicron periods. However, risk factors such as urban residence, underweight, and underlying medical conditions, including chronic cardiac diseases, immunodeficiency, and mental disorders, had different effects on the development of critical COVID-19 illness between the Delta and Omicron periods. CONCLUSION: We found that the severity of COVID-19 infection was much higher for the Delta variant than for the Omicron. Although the Delta and the Omicron variant shared many risk factors for critical illness, several risk factors were found to have different effects on the development of critical COVID-19 illness between those two variants. Close monitoring of a wide range of risk factors for critical illness is warranted as new variants continue to emerge during the pandemic.

Propensity score matched analysis for the safety and effectiveness of remdesivir in COVID-19 patients with renal impairment.

BACKGROUNDS: Remdesivir (RDV) is an antiviral agent approved for the treatment of coronavirus disease 2019 (COVID-19); however, is not recommended for patients with renal impairment. Due to limitations associated with prospective clinical trials, real-world data on the safety and efficacy of RDV in patients with renal impairment are necessary. METHODS: Propensity score-matched (PSM) retrospective analysis was conducted between March 2020 and September 2022 in COVID-19 patients with an eGFR < 30 mL/min in four Korean hospitals. The RDV treatment group was matched to the untreated control group. The safety and clinical outcomes in patients who received RDV were analyzed. RESULTS: A total of 564 patients were enrolled; 229 patients received RDV either for treatment or prophylaxis. On day 5, no difference in nephrotoxicity was observed between the two groups, and liver enzyme levels were within the normal range. In multivariate analysis for new dialysis, RDV treatment was not a risk factor for new dialysis. Among the 564 patients, 417 were indicated for a 5-day course of RDV treatment and 211 patients were treated with RDV. After PSM, no differences in the clinical outcomes were observed between the two groups. CONCLUSION: RDV use in COVID-19 patients with renal impairment did not result in significant nephrotoxicity or hepatotoxicity.

Magnitude and Duration of Serum Neutralizing Antibody Titers Induced by a Third mRNA COVID-19 Vaccination against Omicron BA.1 in Older Individuals.

BACKGROUND: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant (B.1.1.529) is dominating coronavirus disease 2019 (COVID-19) worldwide. The waning protective effect of available vaccines against the Omicron variant is a critical public health issue. This study aimed to assess the impact of the third COVID-19 vaccination on immunity against the SARS-CoV-2 Omicron BA.1 strain in older individuals. MATERIALS AND METHODS: Adults aged ≥60 years who had completed two doses of the homologous COVID-19 vaccine with either BNT162b2 (Pfizer/BioNTech, New York, NY, USA, BNT) or ChAdOx1 nCoV (SK bioscience, Andong-si, Gyeongsangbuk-do, Korea, ChAd) were registered to receive the third vaccination. Participants chose either BNT or mRNA-1273 (Moderna, Norwood, MA, USA, m1273) mRNA vaccine for the third dose and were categorized into four groups: ChAd/ChAd/BNT, ChAd/ChAd/m1273, BNT/BNT/BNT, and BNT/BNT/m1273. Four serum specimens were obtained from each participant at 0, 4, 12, and 24 weeks after the third dose (V1, V2, V3, and V4, respectively). Serum-neutralizing antibody (NAb) activity against BetaCoV/Korea/KCDC03/2020 (NCCP43326, ancestral strain) and B.1.1.529 (NCCP43411, Omicron BA.1 variant) was measured using plaque reduction neutralization tests. A 50% neutralizing dilution (ND50) >10 was considered indicative of protective NAb titers. RESULTS: In total, 186 participants were enrolled between November 24, 2021, and June 30, 2022. The respective groups received the third dose at a median (interquartile range [IQR]) of 132 (125 - 191), 123 (122 - 126), 186 (166 - 193), and 182 (175 - 198) days after the second dose. Overall, ND50 was lower at V1 against Omicron BA.1 than against the ancestral strain. NAb titers against the ancestral strain and Omicron BA.1 variant at V2 were increased at least 30-fold (median [IQR], 1235.35 [1021.45 - 2374.65)] and 129.8 [65.3 - 250.7], respectively). ND50 titers against the ancestral strain and Omicron variant did not differ significantly among the four groups (P = 0.57). NAb titers were significantly lower against the Omicron variant than against the ancestral strain at V3 (median [IQR], 36.4 (17.55 - 75.09) vs. 325.9 [276.07 - 686.97]; P = 0.012). NAb titers against Omicron at V4 were 16 times lower than that at V3. Most sera exhibited a protective level (ND50 >10) at V4 (75.0% [24/32], 73.0% [27/37], 73.3% [22/30], and 70.6% [12/17] in the ChAd/ChAd/BNT, ChAd/ChAd/m1273, BNT/BNT/BNT, and BNT/BNT/m1273 groups, respectively), with no significant differences among groups (P = 0.99). CONCLUSION: A third COVID-19 mRNA vaccine dose restored waning NAb titers against Omicron BA.1. Our findings support a third-dose vaccination program to prevent the waning of humoral immunity to SARS-CoV-2.

The association between antibody responses and prolonged viable SARS-CoV-2 shedding in immunocompromised patients: a prospective cohort study.

Immunocompromised COVID-19 patients were prospectively enrolled from March to November 2022 to understand the association between antibody responses and SARS-CoV-2 shedding. A total of 62 patients were analyzed and the results indicated a faster decline in genomic and subgenomic viral RNA in patients with higher neutralizing and S1-specific IgG antibodies (both P < 0.001). Notably, high neutralizing antibody levels were associated with a significantly faster decrease in viable virus cultures (P = 0.04). Our observations suggest the role of neutralizing antibodies in prolonged virus shedding in immunocompromised patients, highlighting the potential benefits of enhancing their humoral immune response through vaccination or monoclonal antibody treatments.

Virological characteristics and the rapid antigen test as deisolation criteria in immunocompromised patients with COVID-19: A prospective cohort study.

There are limited data supporting current Centers for Disease Control and Prevention guidelines for the isolation period in moderate to severely immunocompromised patients with coronavirus disease 2019 (COVID-19). Adult COVID-19 patients who underwent solid organ transplantation (SOT) or received active chemotherapy against hematologic malignancy were enrolled and weekly respiratory samples were collected. Samples with positive genomic real-time polymerase chain reaction results underwent virus culture and rapid antigen testing (RAT). A total of 65 patients (40 with hematologic malignancy and 25 SOT) were enrolled. The median duration of viable virus shedding was 4 weeks (interquartile range: 3-7). Multivariable analysis revealed that B-cell depletion (hazard ratio [HR]: 4.76) was associated with prolonged viral shedding, and COVID-19 vaccination (≥3 doses) was negatively associated with prolonged viral shedding (HR: 0.22). The sensitivity, specificity, positive predictive value, and negative predictive value of RAT for viable virus shedding were 79%, 76%, 74%, and 81%, respectively. The negative predictive value of RAT was only 48% (95% confidence interval [CI]: 33-65) in the samples from those with symptom onset ≤20 days, but it was as high as 92% (95% CI: 85-96) in the samples from those with symptom onset >20 days. About half of immunocompromised COVID-19 patients shed viable virus for ≥4 weeks from the diagnosis, and virus shedding was prolonged especially in unvaccinated patients with B-cell-depleting therapy treatment. RAT beyond 20 days in immunocompromised patients had a relatively high negative predictive value for viable virus shedding.

Real-World Effectiveness of Nirmatrelvir-Ritonavir and Its Acceptability in High-Risk COVID-19 Patients.

BACKGROUND: Nirmatrelvir-ritonavir is highly effective in preventing severe coronavirus disease 2019 (COVID-19) in high-risk patients with mild-to-moderate severity. However, real-world performance data are limited, and the drug is not so acceptable to the COVID-19 patients at high risk who need it in Korea. METHODS: To evaluate the effectiveness of nirmatrelvir-ritonavir, we conducted a propensity score-matched retrospective cohort study on patients with mild-to-moderate COVID-19 at high risk for a severe disease who were hospitalized at four hospitals in South Korea from February 2022 to April 2022. A total of 236 patients in the treatment group (administered nirmatrelvir-ritonavir) and 236 in the matched control group (supportive care only) were analyzed for the primary outcome, i.e., the time to oxygen support-free survival. The secondary outcome was a composite result of disease progression. The reason for not prescribing nirmatrelvir-ritonavir to the indicated patients was also investigated. RESULTS: The treatment group showed significantly longer oxygen support-free survival than the matched control group (adjusted hazard ratio [aHR], 0.07; 95% confidence interval [CI], 0.01-0.31; P < 0.001). Multivariate Cox regression analysis showed that age (aHR, 1.03; 95% CI, 1.00-1.07), National Early Warning Score-2 at admission (aHR, 1.36; 95% CI, 1.08-1.71), nirmatrelvir-ritonavir treatment, female sex (aHR, 0.37; 95% CI, 0.15-0.88), and time from symptom onset to admission (aHR, 0.67; 95% CI, 0.48-0.95) were significantly associated with oxygen therapy. However, none of the factors were related to the composite outcome. In the unmatched control group, 19.9% of 376 patients had documented explanations for nirmatrelvir-ritonavir non-prescription, and 44.0% of these were due to contraindication criteria. In the treatment group, 10.9% of patients discontinued the medication primarily because of adverse events (71.4%), with gastrointestinal symptoms being the most common (50.0%). CONCLUSION: Nirmatrelvir-ritonavir treatment significantly reduced oxygen therapy requirements in high-risk patients with COVID-19 during the omicron variant surge in South Korea. Physicians are encouraged to consider the active use of nirmatrelvir-ritonavir and to be watchful for gastrointestinal symptoms during medication.

Short-Term Effectiveness of Oral Nirmatrelvir/Ritonavir Against the SARS-CoV-2 Omicron Variant and Culture-Positive Viral Shedding.

BACKGROUND: Information on the effectiveness of nirmatrelvir/ritonavir against the omicron is limited. The clinical response and viral kinetics to therapy in the real world need to be evaluated. METHODS: Mild to moderate coronavirus disease 2019 (COVID-19) patients with risk factors for severe illness were prospectively enrolled as a treatment group with nirmatrelvir/ritonavir therapy versus a control group with supportive care. Serial viral load and culture from the upper respiratory tract were evaluated for seven days, and clinical responses and adverse reactions were evaluated for 28 days. RESULTS: A total of 51 patients were analyzed including 40 in the treatment group and 11 in the control group. Faster symptom resolution during hospitalization (P = 0.048) was observed in the treatment group. Only minor adverse reactions were reported in 27.5% of patients. The viral load on Day 7 was lower in the treatment group (P = 0.002). The viral culture showed a positivity of 67.6% (25/37) vs. 100% (6/6) on Day 1, 0% (0/37) vs. 16.7 (1/6) on Day 5, and 0% (0/16) vs. 50.0% (2/4) on Day 7 in the treatment and control groups, respectively. CONCLUSIONS: Nirmatrelvir/ritonavir against the omicron was safe and resulted in negative viral culture conversion after Day 5 of treatment with better symptomatic resolution.

Kinetics of vaccine-induced neutralizing antibody titers and estimated protective immunity against wild-type SARS-CoV-2 and the Delta variant: A prospective nationwide cohort study comparing three COVID-19 vaccination protocols in South Korea.

Introduction: Despite vaccine development, the COVID-19 pandemic is ongoing due to immunity-escaping variants of concern (VOCs). Estimations of vaccine-induced protective immunity against VOCs are essential for setting proper COVID-19 vaccination policy. Methods: We performed plaque-reduction neutralizing tests (PRNTs) using sera from healthcare workers (HCWs) collected from baseline to six months after COVID-19 vaccination and from convalescent COVID-19 patients. The 20.2% of the mean PRNT titer of convalescent sera was used as 50% protective value, and the percentage of HCWs with protective immunity for each week (percent-week) was compared among vaccination groups. A correlation equation was deduced between a PRNT 50% neutralizing dose (ND50) against wild type (WT) SARS-CoV-2 and that of the Delta variant. Results: We conducted PRNTs on 1,287 serum samples from 297 HCWs (99 HCWs who received homologous ChAdOx1 vaccination (ChAd), 99 from HCWs who received homologous BNT162b2 (BNT), and 99 from HCWs who received heterologous ChAd followed by BNT (ChAd-BNT)). Using 365 serum samples from 116 convalescent COVID-19 patients, PRNT ND50 of 118.25 was derived as 50% protective value. The 6-month cumulative percentage of HCWs with protective immunity against WT SARS-CoV-2 was highest in the BNT group (2297.0 percent-week), followed by the ChAd-BNT (1576.8) and ChAd (1403.0) groups. In the inter-group comparison, protective percentage of the BNT group (median 96.0%, IQR 91.2-99.2%) was comparable to the ChAd-BNT group (median 85.4%, IQR 15.7-100%; P =0.117) and significantly higher than the ChAd group (median 60.1%, IQR 20.0-87.1%; P <0.001). When Delta PRNT was estimated using the correlation equation, protective immunity at the 6-month waning point was markedly decreased (28.3% for ChAd group, 52.5% for BNT, and 66.7% for ChAd-BNT). Conclusion: Decreased vaccine-induced protective immunity at the 6-month waning point and lesser response against the Delta variant may explain the Delta-dominated outbreak of late 2021. Follow-up studies for newly-emerging VOCs would also be needed.

Heterologous ChAdOx1 and Bnt162b2 vaccination induces strong neutralizing antibody responses against SARS-CoV-2 including delta variant with tolerable reactogenicity.

OBJECTIVES: We assessed humoral responses and reactogenicity following the heterologous vaccination compared to the homologous vaccination groups. METHODS: We enrolled healthcare workers (HCWs) who were either vaccinated with ChAdOx1 followed by BNT162b2 (heterologous group) or 2 doses of ChAdOx1 (ChAdOx1 group) or BNT162b2 (BNT162b2 group). Immunogenicity was assessed by measuring antibody titers against receptor-binding domain (RBD) of SARS-CoV-2 spike protein in all participants and neutralizing antibody titer in 100 participants per group. Reactogenicity was evaluated by a questionnaire-based survey. RESULTS: We enrolled 499 HCWs (ChAdOx1, n = 199; BNT162b2, n = 200; heterologous ChAdOx1/BNT162b2, n = 100). The geometric mean titer of anti-receptor-binding domain antibody at 14 days after the booster dose was significantly higher in the heterologous group (11 780.55 binding antibody unit (BAU)/mL [95% CI, 10 891.52-12 742.14]) than in the ChAdOx1 (1561.51 [95% CI, 1415.03-1723.15]) or BNT162b2 (2895.90 [95% CI, 2664.01-3147.98]) groups (both p < 0.001). The neutralizing antibody titer of the heterologous group (geometric mean ND50, 2367.74 [95% CI, 1970.03-2845.74]) was comparable to that of the BNT162b2 group (2118.63 [95% CI, 1755.88-2556.32]; p > 0.05) but higher than that of the ChAdOx1 group (391.77 [95% CI, 326.16-470.59]; p < 0.001). Compared with those against wild-type SARS-CoV-2, the geometric mean neutralizing antibody titers against the Delta variant at 14 days after the boosting were reduced by 3.0-fold in the heterologous group (geometric mean ND50, 872.01 [95% CI, 685.33-1109.54]), 4.0-fold in the BNT162b2 group (337.93 [95% CI, 262.78-434.57]), and 3.2-fold in the ChAdOx1 group (206.61 [95% CI, 144.05-296.34]). The local or systemic reactogenicity after the booster dose in the heterologous group was higher than that of the ChAdOx1 group but comparable to that of the BNT162b2 group. DISCUSSION: Heterologous ChAdOx1 followed by BNT162b2 vaccination with a 12-week interval induced a robust humoral immune response against SARS-CoV-2, including the Delta variant, that was comparable to the homologous BNT162b2 vaccination and stronger than the homologous ChAdOx1 vaccination, with a tolerable reactogenicity profile.

Booster BNT162b2 COVID-19 Vaccination Increases Neutralizing Antibody Titers Against the SARS-CoV-2 Omicron Variant in Both Young and Elderly Adults.

Concerns about the effectiveness of current vaccines against the rapidly spreading severe acute respiratory syndrome-coronavirus-2 omicron (B.1.1.529) variant are increasing. This study aimed to assess neutralizing antibody activity against the wild-type (BetaCoV/Korea/KCDC03/2020), delta, and omicron variants after full primary and booster vaccinations with BNT162b2. A plaque reduction neutralization test was employed to determine 50% neutralizing dilution (ND50) titers in serum samples. ND50 titers against the omicron variant (median [interquartile range], 5.3 [< 5.0-12.7]) after full primary vaccination were lower than those against the wild-type (144.8 [44.7-294.0]) and delta (24.3 [14.3-81.1]) variants. Furthermore, 19/30 participants (63.3%) displayed lower ND50 titers than the detection threshold (< 10.0) against omicron after full primary vaccination. However, the booster vaccine significantly increased ND50 titers against BetaCoV/Korea/KCDC03/2020, delta, and omicron, although titers against omicron remained lower than those against the other variants (P < 0.001). Our study suggests that booster vaccination with BNT162b2 significantly increases humoral immunity against the omicron variant.

Clinical Characteristics of 40 Patients Infected With the SARS-CoV-2 Omicron Variant in Korea.

Since severe acute respiratory syndrome-coronavirus-2 variant B.1.1.529 (omicron) was first reported to the World Health Organization on November 24, 2021, the cases of the omicron variant have been detected in more than 90 countries over the last month. We investigated the clinical and epidemiological characteristics of the first 40 patients with the omicron variant who had been isolated at the National Medical Center in South Korea during December 4-17, 2021. The median age of the patients was 39.5 years. Twenty-two patients (55%) were women. Seventeen patients (42.5%) were fully vaccinated, and none were reinfected with the omicron. Eighteen (45%) had recent international travel history. Half of the patients (19, 47.5%) were asymptomatic, while the others had mild symptoms. Six patients (15%) showed lung infiltrations on chest image; however, none required supplemental oxygen. These mild clinical features are consistent with recent case reports on the omicron variant from other countries.

Genomic characterization of nine Clostridioides difficile strains isolated from Korean patients with Clostridioides difficile infection.

BACKGROUND: Clostridioides difficile infection (CDI) is an infectious nosocomial disease caused by Clostridioides difficile, an opportunistic pathogen that occurs in the intestine after extensive antibiotic regimens. RESULTS: Nine C. difficile strains (CBA7201-CBA7209) were isolated from nine patients diagnosed with CDI at the national university hospital in Korea, and the whole genomes of these strains were sequenced to identify their genomic characteristics. Comparative genomic analysis was performed using 51 reference strains and the nine isolated herein. Phylogenetic analysis based on 16S rRNA gene sequences confirmed that all 60 C. difficile strains belong to the genus Clostridioides, while core-genome tree indicated that they were divided into five groups, which was consistent with the results of MLST clade analysis. All strains were confirmed to have a clindamycin antibiotic resistance gene, but the other antibiotic resistance genes differ depending on the MLST clade. Interestingly, the six strains belonging to the sequence type 17 among the nine C. difficile strains isolated here exhibited unique genomic characteristics for PaLoc and CdtLoc, the two toxin gene loci identified in this study, and harbored similar antibiotic resistance genes. CONCLUSION: In this study, we identified the specific genomic characteristics of Korean C. difficile strains, which could serve as basic information for CDI prevention and treatment in Korea.

Risk Factors and a Scoring System to Predict ARDS in Patients with COVID-19 Pneumonia in Korea: A Multicenter Cohort Study.

Predictive studies of acute respiratory distress syndrome (ARDS) in patients with coronavirus disease 2019 (COVID-19) are limited. In this study, the predictors of ARDS were investigated and a score that can predict progression to ARDS in patients with COVID-19 pneumonia was developed. All patients who were diagnosed with COVID-19 pneumonia between February 1, 2020, and May 15, 2020, at five university hospitals in Korea were enrolled. Their demographic, clinical, and epidemiological characteristics and the outcomes were collected using the World Health Organization COVID-19 Case Report Form. A logistic regression analysis was performed to determine the predictors for ARDS. The receiver operating characteristic (ROC) curves were constructed for the scoring model. Of the 166 patients with COVID-19 pneumonia, 37 (22.3%) patients developed ARDS. The areas under the curves for the infiltration on a chest X-ray, C-reactive protein, neutrophil/lymphocyte ratio, and age, for prediction of ARDS were 0.91, 0.90, 0.87, and 0.80, respectively (all P < 0.001). The COVID-19 ARDS Prediction Score (CAPS) was constructed using age (≥60 years old), C-reactive protein (≥5 mg/dL), and the infiltration on a chest X-ray (≥22%), with each predictor allocated 1 point. The area under the curve of COVID-19 ARDS prediction score (CAPS) for prediction of ARDS was 0.90 (95% CI 0.86-0.95; P < 0.001). It provided 100% sensitivity and 75% specificity when the CAPS score cutoff value was 2 points. CAPS, which consists of age, C-reactive protein, and the area of infiltration on a chest X-ray, was predictive of the development of ARDS in patients with COVID-19 pneumonia.

Antimicrobial susceptibility of Staphylococcus species isolated from prosthetic joints with a focus on fluoroquinolone-resistance mechanisms.

We investigated susceptibility to antimicrobials of 89 staphylococcal species from PJIs and analyzed fluoroquinolone (FQ)-resistance mechanisms. Staphylococcal isolates showed high resistance to oral antimicrobials, with the exception of TMP-STX and linezolid. The main mechanism of resistance to FQ was mutations in quinolone-resistance-determining-regions. Fifteen percent of Staphylococcus aureus overexpressed efflux-pump genes.

Dysfunctional accessory gene regulator (agr) as a prognostic factor in invasive Staphylococcus aureus infection: a systematic review and meta-analysis.

The accessory gene regulator (agr) locus of Staphylococcus aureus is a quorum-sensing virulence regulator. Although there are many studies concerning the effect of dysfunctional agr on the outcomes of S. aureus infection, there is no systematic review to date. We systematically searched for clinical studies reporting outcomes of invasive S. aureus infections and the proportion of dysfunctional agr among their causative strains, and we performed a meta-analysis to obtain estimates of the odds of outcomes of invasive S. aureus infection with dysfunctional versus functional agr. Of 289 articles identified by our research strategy, 20 studies were meta-analysed for crude analysis of the impact of dysfunctional agr on outcomes of invasive S. aureus infection. Dysfunctional agr was generally associated with unfavourable outcomes (OR 1.32, 95% CI 1.05-1.66), and the impact of dysfunctional agr on outcome was more prominent in invasive methicillin-resistant S. aureus (MRSA) infections (OR 1.54, CI 1.20-1.97). Nine studies were meta-analysed for the impact of dysfunctional agr on the 30-day mortality of invasive S. aureus infection. Invasive MRSA infection with dysfunctional agr exhibited higher 30-day mortality (OR 1.40, CI 1.03-1.90) than that with functional agr. On the other hand, invasive MSSA infection with dysfunctional agr exhibited lower 30-day mortality (OR 0.51, CI 0.27-0.95). In the post hoc subgroup analysis by the site of MRSA infection, dysfunctional agr was associated with higher 30-day mortality in MRSA pneumonia (OR 2.48, CI 1.17-5.25). The effect of dysfunctional agr on the outcome of invasive S. aureus infection may vary depending on various conditions, such as oxacillin susceptibility and the site of infection. Dysfunctional agr was generally associated with unfavourable clinical outcomes and its effect was prominent in MRSA and pneumonia. Dysfunctional agr may be applicable for outcome prediction in cases of invasive MRSA infection with hardly eradicable foci such as pneumonia.

Prosthetic valve endocarditis by Trichosporon mucoides: A case report and review of literature.

NATIONALE: Trichosporon species are widely distributed in nature and are emerging opportunistic human pathogens. Trichosporon infections are associated with superficial cutaneous involvement in immunocompetent individuals to severe systemic disease in immunocompromised patients. Until now, there is no report in infective endocarditis by Trichosporon mucoides confirmed by molecular diagnostics PATIENT CONCERNS:: A 66-year-old man presented with a fever that had occurred for a period of 6 months. He had undergone aortic valve replacement 10 years prior. Transthoracic echocardiography showed vegetations on the prosthetic aortic valve and native mitral valve. T mucoides was detected in the cultures of blood and vegetations. DIAGNOSIS: DNA sequencing using D/D2 region of rRNA and internal transcribed spacer were performed. INTERVENTIONS: Infections were successfully controlled with valve replacement and voriconazole plus liposomal amphotericin B therapy. OUTCOMES: There has been no sign of recurrence for 18-months after treatment completion. LESSONS: This is the first reported case of infective endocarditis due to T mucoides. Clinicians should consider Trichosporon species as causative agents of endocarditis in patients who have undergone cardiac surgery.

Air and Environmental Contamination Caused by COVID-19 Patients: a Multi-Center Study.

BACKGROUND: The purpose of this study was to determine the extent of air and surface contamination of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in four health care facilities with hospitalized coronavirus disease 2019 (COVID-19) patients. METHODS: We investigated air and environmental contamination in the rooms of eight COVID-19 patients in four hospitals. Some patients were in negative-pressure rooms, and others were not. None had undergone aerosol-generating procedures. On days 0, 3, 5, and 7 of hospitalization, the surfaces in the rooms and anterooms were swabbed, and air samples were collected 2 m from the patient and from the anterooms. RESULTS: All 52 air samples were negative for SARS-CoV-2 RNA. Widespread surface contamination of SARS-CoV-2 RNA was observed. In total, 89 of 320 (27%) environmental surface samples were positive for SARS-CoV-2 RNA. Surface contamination of SARS-CoV-2 RNA was common in rooms without surface disinfection and in rooms sprayed with disinfectant twice a day. However, SARS-CoV-2 RNA was not detected in a room cleaned with disinfectant wipes on a regular basis. CONCLUSION: Our data suggest that remote (> 2 m) airborne transmission of SARS-CoV-2 from hospitalized COVID-19 patients is uncommon when aerosol-generating procedures have not been performed. Surface contamination was widespread, except in a room routinely cleaned with disinfectant wipes.

Viral Load Kinetics of SARS-CoV-2 Infection in Saliva in Korean Patients: a Prospective Multi-center Comparative Study.

BACKGROUND: This study was performed to compare the viral load and kinetics of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in saliva with those in standard nasopharyngeal/oropharyngeal (NP/OP) swabs. METHODS: Fifteen patients with SARS-CoV-2 infection from four hospitals were prospectively enrolled and matched samples of nasopharyngeal/oropharyngeal swabs and saliva were collected at Day 1 of admission and every other day till consequently negative for two times. Real-time reverse transcription polymerase chain reaction (rRT-PCR) was performed to detect the envelope (E) and RNA-dependent RNA polymerase (RdRP) genes. RESULTS: The cycle threshold values of saliva were comparable to those of NP/OP swabs overall (P = 0.720, Mann-Whitney U test). However, the overall sensitivity of rRT-PCR using saliva was 64% (34/53), which is lower than the 77% (41/53) using NP/OP swabs. The sensitivity of rRT-PCR using saliva was especially lower in early stage of symptom onset (1-5 days; 8/15; 53%) and in patients who did not have sputum (12/22; 55%). CONCLUSION: Saliva sample itself is not appropriate for initial diagnosis of coronavirus disease 2019 (COVID-19) to replace NP/OP swabs, especially for the person who does not produce sputum. COVID-19 cannot be excluded when the test using saliva is negative, and it is necessary to retest using NP/OP swabs.

Microbial Etiology of Pyogenic Vertebral Osteomyelitis According to Patient Characteristics.

BACKGROUND: It is difficult to select an appropriate empirical antibiotic treatment regimen for patients with culture-negative pyogenic vertebral osteomyelitis (PVO). Having knowledge of the distribution of microorganisms according to patient characteristics can help clinicians make informed choices regarding empirical antibiotics. The aim of this study was to determine the microbial distribution among individuals with PVO according to their demographic and clinical characteristics. METHODS: We reviewed the medical records of patients admitted to our hospital with culture-confirmed PVO between January 2005 and December 2017 and collected data on demographics, underlying diseases, and radiographic and microbiological results. Statistical analysis was performed to identify associations between specific bacteria and specific patient characteristics. RESULTS: A total of 586 patients were included in the study. The prevalence of Staphylococcus aureus infections was higher in young patients than in old patients, while gram-negative bacterial infections and Enterococcus were more prevalent in older patients. Gram-negative bacterial infections were more common in women than in men (32.1% vs 16.4%; P < .05), in patients with cirrhosis than in those without (32.7% vs 21.1%; P < .05), and in patients with a solid tumor than in those without (31.0% vs 20.7%; P < .05). Methicillin-resistant S. aureus infections were more prevalent in patients with chronic renal disease than in those without (34.4% vs 14.7%; P < .05). CONCLUSIONS: The microbial etiology of PVO varies according to patient characteristics. Patient characteristics should thus be considered when choosing empirical antibiotics in patients with culture-negative PVO.